Object looks fine in rendered mode, but appears black in material mode
Procedural textures (such as noise) will not render in Material Shading




  From the Manual:
  
  Shading refers to the way objects are drawn and lit in the 3D View.
  
  Rendered
  
  An accurate representation using the selected Render Engine and lit with the visible scene lights.
  
  Material
  
  A fast approximation of the applied material. Some effects, such as procedural textures may not be shown.
  
  Textured
  
  Shows meshes with an image applied using the mesh’s active UV Map. For Cycles materials, the image is the last one selected in the Node Editor. For other render engine’s, the UV Map’s applied face texture will be shown.
  
  Solid
  
  The default drawing mode using solid colored surfaces and simple lighting.
  
  Wireframe
  
  Objects appear as a mesh of lines representing the edges of faces and surfaces.
  
  Bounding Box
  Shows only the rectangular boxes that outlines an object’s size and shape.


When you have a mix node, the color connected used in the bottom socket becomes the one used in the 3D viewport's material shading: